Pre-assembled manifold systems are resin distribution systems that are pre-wired and pre-plumbed for installation into a set of plates, such as manifold and cavity plates. For example, a manifold system may include a sprue to receive melt from a machine nozzle, a distribution manifold, actuators for valve gate systems if used, and nozzle stack components. The nozzle(s) or nozzle stack(s) must be aligned with receiving bores in the plates as the distribution manifold is located and supported by insulators that contact the plates.